The present invention relates generally to techniques for designing integrated circuits (ICs). Specifically, the present invention relates to the use of a software graphic editor for designing logic devices using one or more high level block diagrams.
Despite the prevalence of sophisticated design software and automated manufacturing techniques, the first step in designing often involves a hand drawn block diagram in a designer""s notebook. The hand drawn block diagram is typically used as a tool for organizing the thoughts of the designer as to the high-level architecture and functionalities of the device but is not typically used as a software design entry point. In fact, several levels of such hand drawn block diagrams of increasing detail are often employed until the level of detail reaches a point where currently available software design tools can provide design elements having the requisite functionalities.
There are computer aided drawing (CAD) tools with which a designer can create such block diagrams in a graphical user interface. However, such CAD tools do not interface with the design tools used for defining the circuit level implementation of the blocks in the block diagram. Even with an electronically created block diagram, unrelated design files must be created for the implementation of the individual blocks of the diagram. That is, a block diagram created with a currently available CAD tool is about as useful as a hand drawn block diagram with regard to the circuit level implementation of a design.
It is therefore apparent that there is a need for a design tool which will enable the designer not only to create high level block diagrams, but to actually use these diagrams in the software environment as a design entry point, and moreover to use the diagrams in conjunction with existing design tools to implement gate level design.
According to the present invention a graphic editor is provided which enables IC designers to create and use block diagrams of varying levels of detail as design entry points, and to use these block diagrams in conjunction with a wide variety of existing design file editors, e.g., AHDL, VHDL, and Verilog editors, to implement down to gate level design. Rather than drawing a block diagram in a notebook, the designer uses the graphic editor of the present invention to create the block diagram on his workstation screen using visual representations selected in the editor""s graphical user interface (GUI). The designer specifies input and outputs for each block in the diagram and interconnects the blocks with generalized conduits each representing one or more of the actual connections between the blocks. The designer then specifies the signal names in the conduits and maps the signal names to the inputs and outputs of the various blocks.
If necessary, the designer may use the editor in much the same way to create increasingly detailed block diagrams corresponding to each of the blocks in a higher level diagram. A separate graphic design file is created for each block diagram on each level of the architecture hierarchy. Once the designer has specified the design to a sufficient level of detail, he can create a circuit level implementation of the blocks in any of a variety of design file formats using a variety of design file editors including, for example, AHDL, VHDL, and Verilog editors. According to a specific embodiment of the invention, the block diagrams created using the graphic editor of the present invention are employed in combination with design file templates to create design files in the design file format favored by the individual designer. That is, using the block specifications in the block diagram and a design file template of a particular format, an incomplete design file is created in the desired format within which the designer may then specify the function of the corresponding block.
Thus, according to the present invention, a method is described for designing a circuit using graphic editor software. A graphic design file is generated corresponding to a block diagram created in a graphical user interface associated with the graphic editor software. The block diagram includes a plurality of blocks and a plurality of conduits interconnecting the blocks. A block design file is generated in one of a plurality of formats for each of selected ones of the plurality of blocks in the block diagram. Each of the block design files corresponds to an implementation of its corresponding block. Modifications to any of the graphic design file and the block design files are incorporated into each other under software control.